This invention relates to an induction system for an engine and more particularly to an improved induction system for a vehicle engine.
The performance of an engine is obviously quite dependent upon the efficiency of its induction system. If the induction system is not properly configured, the mount of air flow to the engine can be either obstructed or restricted under at least some running conditions, and result in poor engine performance. This problem is particularly acute in conjunction with multiple cylinder engines. In many regards, it would be desirable if each cylinder of the engine could be supplied with its own induction system which would be independent of those of the other cylinders. However, practicality simply does not permit this. This is particularly true when it is desirable to simplify the engine through the utilization of a single throttle valve control for controlling the flow of air to all cylinders.
Therefore, multiple cylinder engine induction systems generally include a plenum chamber which has a tuned and relatively large volume and to which air is delivered from the atmosphere through a speed controlling throttle valve. The plenum chamber then communicates with the individual cylinders which it serves through runner passages that extend from the plenum chamber to those cylinders. This type of system has been found to be effective in minimizing adverse effects from the common air inlet that supplies multiple cylinders. That is, the plenum chamber, if it has sufficient volume, can dampen pulsations from one cylinder before they adversely affect the charge flow to another cylinder served by the same plenum chamber. Also, by appropriately tuning the volume of the plenum chamber and the length of the framer sections, it is possible to improve engine performance, particularly at specifically targeted engine speed and/or lead conditions.
Although in theory this concept is quite sensible, it is difficult to follow in actual practice. One reason for this is the space constraints under which most engines operate. These space constraints are particularly prevalent in applications for powering motor vehicles such as automobiles. Basically, the engine compartment of a motor vehicle is relatively small and not always regularly configured because of the intrusion of suspension systems and other components. In addition, there is a desire to maintain a low hood line so as to permit streamlining of the body configuration and lower drag. This obviously makes the problem of the designer in laying out and in configuring the induction system quite difficult.
These problems are further compounded when the engine is mounted in the engine compartment so that its output shaft rotates about a transverse rather than a longitudinally extending direction. In many vehicle configurations, such transverse engine placement is utilized so as to further minimize the spatial requirements of the engine. However, this minimization of the spatial requirements further aggravates the problem of defining an effective induction system.
These problems are further compounded when the engine in question is of the V-type and has angularly disposed cylinder banks. Such V-type engines offer the advantages of being compact, but when placed transversely in the engine compartment, additional problems arise. This is particularly hue when the engine compartment is enclosed by a downwardly sloping hood. With such arrangements, the forwardmost cylinder bank will be disposed much closer to the hood line than the rearwardmost cylinder bank. This further aggravates the problem of providing an effective induction system.
It is, therefore, a principal object of this invention to provide an improved induction system for an automotive or vehicular engine.
It is a still further object of this invention to provide a compact and high-efficiency induction system for a multi-cylinder engine.
It is a still further object of this invention to provide an improved induction system for an engine that is disposed transversely in an engine compartment.
It is a final and additional principal object of this invention to provide an improved induction system for, a V-type automotive engine.